<?php
$file = $_GET['file'];
$download_path = "../admin/ImageUpload/files/".$file;
if(!file_exists($download_path)){
    die("I'm sorry, the file doesn't seem to exist."); 
}
header ("Content-type: octet/stream");
header ("Content-disposition: attachment; filename=".$file.";");
header ("Content-Transfer-Encoding: binary");
header ("Content-Length: ".filesize($file));
readfile($file);
exit;
?>